Warfarin Self-Monitoring Offers Benefits

February 13, 2006 -- People who take anti-clotting drug warfarin and self-monitor their blood levels,
rather than having a laboratory monitor them, may be much better
off, according to a study
published in The Lancet and reported by
Healthday.com on February 3, 2006.

Researchers Dr Carl Heneghan, a clinical research fellow at
Oxford, and colleagues found that people who monitor their own
blood warfarin levels have a significantly lower risk of major
adverse events and mortality.

The purpose of the study was to "fill a knowledge gap",
according to HealthDay, and the researchers wrote about the
self-monitoring technique, "Published guidelines state that there
are no reliable clinical-outcome data in any of the published
studies to lend support to its use."

The results showed that self-monitoring was associated with a
55% lower rate of harmful clotting events, a 39% lower death rate
(from all causes) and a 35% lower rate of major bleeding crises,
compared with laboratory monitoring.

Lead author Dr Heneghan said that the study was initially
intended only to demonstrate the safety of self-monitoring,
according to Healthday.com. The additional findings that
self-monitoring is associated with substantial health benefits was
surprising.

"Each of the trials alone was not statistically significant, but
combining them showed that you get a benefit in terms of
mortality," he said, according to Healthday.com. He added that
warfarin self-monitoring may be compared to people with diabetes'
self-monitoring their blood sugar levels.

"It offers a sense of freedom, of not being tied to a clinic,"
he reportedly said.

Warfarin reduces the clotting ability of blood, but is difficult
to manage and required constant monitoring with blood tests to
ensure that the person's blood can still clot within the normal
range. People who take Coumadin must often test themselves weekly
or every few weeks, for years.

A Low Rate of Self-Monitoring

The US Food and Drug Administration (FDA) has approved warfarin
self-monitoring equipment, but less than 1% of doctors permit their
patients to self-monitor, according to Gary Liska, director of the
disease management group of the company Quality Assured Services,
which markets three types of monitor.

One reason for the low rate of self-monitoring is that Medicare
will cover the cost of the equipment only for people who have
artificial heart valves, Liska reportedly said. However, warfarin
may be prescribed for several other reasons, such as atrial
fibrillation.

Liska also noted that perhaps medical professionals "fear of
loss of control of patients. We feel that in reality the opposite
is true, that patients have better control than ever before."

Fear of malpractice suits is another concern, in cases where
self-monitoring goes awry. For example, warfarin interacts with
several other drugs, and the risk of harmful drug-drug interactions
is increased in the elderly population, who often take several
medications at once. (To find out about the interactions between
warfarin and other drugs, please visit the Drugs.com Drug Interactions Checker.)

Intensive patient training and the high cost of test-strips may
also contribute to the low rate of self-monitoring. However, once
people learn the technique, the test requires only a fingerstick,
similar to the test that people with diabetes perform to measure
blood glucose.

If a warfarin-level reading is outside the range set by their
physician, the person can call the doctor to find out about
changing their dosage.

However, with regard to patients being able to self-monitor
their own warfarin levels, "many doctors seem to have a roadblock
in their minds," Liska reportedly said.